Coastal pith starts salty. A wash lowers that salt. Buffering is a different step: potassium and sodium are exchanged toward calcium and magnesium so the mix does not fight the feed.
The 5 kg block lists three grades on one URL: unwashed, washed low-EC, buffered. The briquette lists unwashed or washed. We do not call unwashed premium. Moisture, expansion, and pH stay as dashes on those pages until a mill sheet fills them — this note will not invent the numbers.
If the purchase order says “washed” and the grower needed a buffer, the COA will not save the crop. Name the grade that is already on the line. Growing media is the floor; quality is how to read it.